Dry kiln



Oct. 9 1923. y 1,469,976

J. PfwALsH DRY KILN Filed Oct. 19. 1922 /NVENTOR JOSEPH PATR/CK WALSH ATTORNEYS tiene a rr.

JOSEPH PATRICK WALS, OF VANCOUVER, BRITISH COLUMBIA, CANADA. I

DRY KILN.

.application filed October 19,' 1922. Serial No. 595,648.

y T o aZZ whom t may concern Be it known that l, JOSEPH PATRICK WALSH, a resident of the city of Vancouver, in the Province of British Columbia, Canada, have invented certain new and-useful Improvements in D Kilns, of which the following is a specincation.

My invention relates to improvements in dry kilns and the object of the invention is to devise simple means which may be installed in existing kilns and which may be easily operated and automatically controlled for drying lumber without danger of checking or warping and without drying out the sap so rapidly Aas to permanently injure the material.

lt consists essentiall of air supply ducts running lengthwise o the kiln with apertures spaced apart longitudinally thereof to discharge the heated air into the kiln, and air return ducts with apertures similarly spaced to receive the cooled air and conduct it from the kiln.

A heating chamber with steam coils therein attached to a power driven blower for circulating the air from the returns to the su ply ducts etc.

team coils placed inthe supply ducts and a steam line running along each supply duct provided with jets arranged along its length to discharge wet steam to permeate the heated air supply with moisture as hereafter more particularly described.

Fig. 1 is a plan of the kiln.

Fig. 2 is a sectional view showin the arrangement of the blower and the air ducts, taken on the line 2 2.

Fig. 3 is a sectional view of the kiln and thermostatic connections.

Fig. 4 is a longitudinal section of my air su ply duct.

ig. 5 is a longitudinal view showing a modification of same.

In the drawings like 'characters of reference indicate corresponding parts in each figure.

4Numeral 1 designates a blower room which may be attached tothe dry kiln room 2 as herein shown or the said blower and dry kiln rooms may be disposed in any other desired relative relation consistent with the purposes of the invention.

The heating chamber 3 is attached to blower 4 and has-within it a series of steam coils 5 which are supplied with steam from any desiredsource.

The blower is mechanically driven and may be of any desired form i and is connected by its downwardly projecting discharge duct to a lateral connection 6 and to the hot air supply ducts'7.

At the entrance to ducts 7 are arranged plurality of super-heating steam coils 8 for approximate y the entire length of the' ducts.

At one side of each aperture 10 is positioned a delector plate 11, slee Fig. 4, such deiiector bein attached to the underside of the cover of uct 7, and is set at an angle7 with its lower extremity pointing` opposite the direction of the How of air through the ducts for the purpose of directing the How of air from the blower upwards through each of the said apertures.

12 is a return duct extending substantially the full length of the kiln, it is rectangular in cross section and is lformed with the bottom sloping Iupwards' from the blower end in a similar manner to the supply ducts. Rectangular apertures 13 are provided inthe cover of the duct 12, which are spaced l apart throughout the length o f the duct, the length of the ducts running crosswise of the duct cover.

Steam conduits 14 are lconnected. to the steam supply and extend along the bottoms of the ducts 7 being spaced preferablymidway between their sides at regular intervals. Along said steam conduit T-connections are made to which are fitted steam jets 15 set vertically for the emission of wet steam into the current of hot air and also for the purpose of accelerating the passage of air and moisture through the apertures 10.

Disposed within the lengthjf pipe lines supplying steam -to the super-heatin coils 8 is a diaphragm operated valve 16, w ich is actuated by compressed air or other suitable means from instru-ment board 17 in conjunction with a thermostatic bulb 18 set to project into the kiln through one of the walls thereof.

19 is a diaphragm operated valve on the pipe line conveying steam to conduits 14 'and jets 15 within the hot air ducts 7, which is actuated by compressed air or other suitable means from instrument board 17 in conjunction with a thermostatic bulb or switch 20 preferably mounted on the ceiling of the kiln and also by a time clock'mechanism to start or stop the moisture irrespectiveof the thermostatic control.

n the instrument board" 17 are mounted a clock 21 and steam valve controlling instruments 22 and 23.

2d in Fig. 5, is a modified `form of delector plate attached to supply duct cover adjacent the aperture 25, such deflector being formed curving downwardy from the cover its lower edge pointing against the fiowair along the duct.

l will now briefly describe the operation of my invention.

rlhe lumber to be dried is run into the kiln on trucks running on rails in the usual way i the lumber being spaced apart to allow for free circulation of -air around the several pieces as illustrated in Fig. 3.

rllhe steam controlling instruments are set to register a desired temperature and humidity, the steam is turned on and blower started.

Air is' drawn by the'blower through the primary heating coils and passed along lateral duct 6, thence through coils 8 where it is 'heated to a temperature greater than the maximum set on control instrument 22 and passed along ducts 7 where it is impregnated with wet steam emanating from ]ets which is set to discharge vertically upwards, have a tendency to drive the moistened hot air through the apertures 10.

The inclined bottoms of theducts 7 and deectors 11 attached to the cover of the dal@ ducts tend to cause a regular and even discharge yot' air through each of the said apertures throughout the length of the ducts. The superheated and moistened air rapl idlyrises to the top of the kiln-and in descending, through cooling and suction, the moisture vcondenses upon the lumber to be dried until the entire mass is raised to a temperature equivalent to the incoming air when it becomes vapourized and is retained in suspension in the air solong as the steam va our is allowed to discharge therein.

n the air cooling and descending to the .floor of the kiln it is drawn evenly downward along the entire length of the kiln through the apertures 13 of return duct 12 and into heating chamber 3, when the cycle is repeated.-

From this description it will be seen that ll have devised a kiln whereby lumber may be dried without checking or warping by impregnating the lumber with moisture or wet stea in such a manner as to rst parraedern .such material is dried from the centre outward instead of as in kilns of common use,

'drying the material from its outer surface towards the centre thereof, so as to result in the checking or warping of the material and also in the sap drying out so rapidly as to permanently injure the material so dried.

What l claim as my invention is:

v 1. In a dry kiln, the combination with the dryingchamber, of a heating chamber, ducts extending from the heating chamber forwardly through the drying chamber, a return duct, lmeans for distributing the heated air from the forwardly extending ducts through the drying chamber of the kiln, and means for moistening such heated air as it passes through the ducts.

2. ln a dry kiln, the combination with the drying chamber, of a heating chamber, ducts extending from the heating chamber forwardly through the drying chamber, a

return duct, means for distributing the heated air from the forwardly extending ducts through the drying chamber ofthe kiln, means for moistening such heated air as .it passes through the ducts, and automatic means for cutting od' the moisture supply when the required temperature is reached.

3. In a dry kiln, the combination with the drying chamber of a kiln, of a heating chamber, a blower .tan connecte'dto the heating chamber, a duct extending forlwardly from the blower `fan through the heating chamber, a return duct extending longitudinally through the drying chamber to the heating chamber, means for distributing the heated air from the forwardly extending ducts, and means for moistening,

the airuas it passes through such forwardly extending ducts.

, d. ln a dry kiln, the combination with a drying kiln, of heated air supplying ducts and a supply duct and return duct each having slit openings extending crosswise of the top thereof having forwardly deiected fins depending from the rearward edge of.

each slit opening, and a heating device for heating and circulating the air through the supply duct and back through ythe return duct to the heating source.

5. ln a dry kiln, the combination with a drying 'Chambanet air supply ducts extending longitudinally of each side of the chamber and having air distributing openings in the upper wall thereof, a heating chamber and blower fan, a connecting duct connecting each of the supply ducts with the blower fan, a return duct having return -tseeegove openings in the tippen Well thereof end leading to the heating chamber, and 'means for niostening the air es it is supplied to the drying chamher.

6. lin e dey kiln, the combination with e drying chamber, of ein supply ducts extending longitudinally of each side of the ehemher and having air distributing openings in 'the upper Well thereof, a, heating chemloer and blower tten, e connecting duct connesting each of the supply ducts with the blower fan, a return oluet, having ietum openings in the uppei' Well thereof and leading to the heating chamber, e pipe eX- tending;r longitudinally through the air supply duets., .end steam jets extending up- Werdly therefrom et suitable distances apart. f

Dated et Vancouver, B. C., this 3rd day of @ctooen 1922;

. JSEPH PATRICK WALSH. Witnesses:

J, L Tomes-on, Rennen E. CARVER. 

